Utilities

Utilities — Various helper and utility functions.

Synopsis

#include <mirage-utils.h>

#define             MIRAGE_CAST_DATA                    (buf,
                                                         off,
                                                         type)
#define             MIRAGE_CAST_PTR                     (buf,
                                                         off,
                                                         type)
enum                MirageSubChannel;
guint8              mirage_helper_ascii2isrc            (gchar c);
gint                mirage_helper_bcd2hex               (gint bcd);
MirageTrackModes    mirage_helper_determine_sector_type (const guint8 *buf);
const gchar *       mirage_helper_encoding_from_bom     (const guint8 *buffer);
gchar *             mirage_helper_find_data_file        (const gchar *filename,
                                                         const gchar *path);
const gchar *       mirage_helper_get_suffix            (const gchar *filename);
gboolean            mirage_helper_has_suffix            (const gchar *filename,
                                                         const gchar *suffix);
gint                mirage_helper_hex2bcd               (gint hex);
gchar               mirage_helper_isrc2ascii            (guint8 c);
void                mirage_helper_lba2msf               (gint lba,
                                                         gboolean diff,
                                                         guint8 *m,
                                                         guint8 *s,
                                                         guint8 *f);
gchar *             mirage_helper_lba2msf_str           (gint lba,
                                                         gboolean diff);
gint                mirage_helper_msf2lba               (guint8 m,
                                                         guint8 s,
                                                         guint8 f,
                                                         gboolean diff);
gint                mirage_helper_msf2lba_str           (const gchar *msf,
                                                         gboolean diff);
void                mirage_helper_sector_edc_ecc_compute_ecc_block
                                                        (const guint8 *src,
                                                         guint32 major_count,
                                                         guint32 minor_count,
                                                         guint32 major_mult,
                                                         guint32 minor_inc,
                                                         guint8 *dest);
void                mirage_helper_sector_edc_ecc_compute_edc_block
                                                        (const guint8 *src,
                                                         guint16 size,
                                                         guint8 *dest);
gint                mirage_helper_strcasecmp            (const gchar *str1,
                                                         const gchar *str2);
gint                mirage_helper_strncasecmp           (const gchar *str1,
                                                         const gchar *str2,
                                                         gint len);
void                mirage_helper_subchannel_deinterleave
                                                        (gint subchan,
                                                         const guint8 *channel96,
                                                         guint8 *channel12);
void                mirage_helper_subchannel_interleave (gint subchan,
                                                         const guint8 *channel12,
                                                         guint8 *channel96);
guint16             mirage_helper_subchannel_q_calculate_crc
                                                        (const guint8 *data);
void                mirage_helper_subchannel_q_decode_isrc
                                                        (const guint8 *buf,
                                                         gchar *isrc);
void                mirage_helper_subchannel_q_decode_mcn
                                                        (const guint8 *buf,
                                                         gchar *mcn);
void                mirage_helper_subchannel_q_encode_isrc
                                                        (guint8 *buf,
                                                         const gchar *isrc);
void                mirage_helper_subchannel_q_encode_mcn
                                                        (guint8 *buf,
                                                         const gchar *mcn);
guint16             mirage_helper_calculate_crc16       (const guint8 *data,
                                                         guint length,
                                                         const guint16 *crctab,
                                                         gboolean reflected,
                                                         gboolean invert);
guint32             mirage_helper_calculate_crc32       (const guint8 *data,
                                                         guint length,
                                                         const guint32 *crctab,
                                                         gboolean reflected,
                                                         gboolean invert);

Description

These functions cover various functionality. They are exported because, while primarily designed to be used within libMirage, they could also prove useful to other applications.

Details

MIRAGE_CAST_DATA()

#define MIRAGE_CAST_DATA(buf,off,type) (*((type *)(buf+off)))

A macro for easy retrieval of data from (unsigned integer) buffer. Mostly to be used in binary image parsers, for example, to retrieve guint32 or guint16 value from buffer.

buf :

buffer to get data from

off :

offset in buffer at which to get data

type :

data type (i.e. 'guint64')

MIRAGE_CAST_PTR()

#define MIRAGE_CAST_PTR(buf,off,type) ((type)(buf+off))

A macro for easy placing of pointers within (unsigned integer) buffer. Mostly to be used in binary image parsers, for example, to retrieve a string or a structure from buffer.

buf :

buffer to place pointer in

off :

offset in buffer at which to place pointer

type :

pointer type (i.e. 'gchar *')

enum MirageSubChannel

typedef enum {
    SUBCHANNEL_W = 0,
    SUBCHANNEL_V = 1,
    SUBCHANNEL_U = 2,
    SUBCHANNEL_T = 3,
    SUBCHANNEL_S = 4,
    SUBCHANNEL_R = 5,
    SUBCHANNEL_Q = 6,
    SUBCHANNEL_P = 7,
} MirageSubChannel;

Subchannel type for interleaving/deinterleaving.

SUBCHANNEL_W

W subchannel data

SUBCHANNEL_V

V subchannel data

SUBCHANNEL_U

U subchannel data

SUBCHANNEL_T

T subchannel data

SUBCHANNEL_S

S subchannel data

SUBCHANNEL_R

R subchannel data

SUBCHANNEL_Q

Q subchannel data

SUBCHANNEL_P

P subchannel data

mirage_helper_ascii2isrc ()

guint8              mirage_helper_ascii2isrc            (gchar c);

Converts ASCII character c into ISRC character.

c :

ASCII character. [in]

Returns :

ISRC character

mirage_helper_bcd2hex ()

gint                mirage_helper_bcd2hex               (gint bcd);

Converts bcd-encoded integer into hex-encoded integer.

bcd :

bcd-encoded integer. [in]

Returns :

hex-encoded integer

mirage_helper_determine_sector_type ()

MirageTrackModes    mirage_helper_determine_sector_type (const guint8 *buf);

Determines sector type from its data, based on first 16 bytes, which correspond to sync pattern and header.

This function is intened to be used in image parsers, for determining track mode in cases when full (2352-byte) sector data is available.

buf :

buffer containing at least first 16 bytes of sector's data. [in]

Returns :

sector type (one of MirageTrackModes)

mirage_helper_encoding_from_bom ()

const gchar *       mirage_helper_encoding_from_bom     (const guint8 *buffer);

Tries to decode BOM provided in buffer, and based on the result returns the following encodings: UTF-32BE, UTF32-LE, UTF-16LE, UTF-16BE or UTF-8 (if BOM is not valid).

buffer :

a 4-byte buffer containing BOM. [in][transfer none][array fixed-size=4]

Returns :

the name of encoding, or NULL if UTF-8 is assumed. The string is statically stored and should not be modified. [transfer none]

mirage_helper_find_data_file ()

gchar *             mirage_helper_find_data_file        (const gchar *filename,
                                                         const gchar *path);

Attempts to find a file with filename filename and path path. filename can be file's basename or an absolute path. path can be either directory path (in this case, it must end with '/') or a filename (i.e. of file descriptor).

If filename is an absolute path, its existence is first checked. If it does not exist, search (see below) is performed in filename's dirname. If still no match is found and path is not NULL, path's dirname is combined with filename's basename, and the combination's existence is checked. If that fails as well, search (see below) is performed in path's dirname. Searching in the directory is performed as follows. Directory is opened and its content is case-insensitively compared to filename's basename. All filenames whose beginning match filename are considered, and the shortest one is returned. This way, all possible case variations (i.e. file.iso, FILE.ISO, FiLe.IsO, etc.) are taken into account. This function can return a filename with additional suffices, but only if a file without those extra suffices does not exist. E.g., if search is done for 'data.img', and only 'data.img.gz' exists, it will be returned. However, if both 'data.img' and 'data.img.gz' exist, the former will be returned. The returned string should be freed when no longer needed.

filename :

declared filename. [in]

path :

path where to look for file (can be a filename), or NULL. [in][allow-none]

Returns :

a newly allocated string containing the fullpath of file, or NULL.

mirage_helper_get_suffix ()

const gchar *       mirage_helper_get_suffix            (const gchar *filename);

Retrieves suffix from filename.

filename :

filename. [in]

Returns :

pointer to character in filename at which the suffix starts. [transfer none]

mirage_helper_has_suffix ()

gboolean            mirage_helper_has_suffix            (const gchar *filename,
                                                         const gchar *suffix);

Checks whether file name filename ends with suffix suffix.

filename :

filename. [in]

suffix :

suffix. [in]

Returns :

TRUE if filename contains suffix suffix, FALSE if not

mirage_helper_hex2bcd ()

gint                mirage_helper_hex2bcd               (gint hex);

Converts hex-encoded integer into bcd-encoded integer.

hex :

hex-encoded integer. [in]

Returns :

bcd-encoded integer

mirage_helper_isrc2ascii ()

gchar               mirage_helper_isrc2ascii            (guint8 c);

Converts ISRC character c into ASCII character.

c :

ISRC character. [in]

Returns :

ACSII character

mirage_helper_lba2msf ()

void                mirage_helper_lba2msf               (gint lba,
                                                         gboolean diff,
                                                         guint8 *m,
                                                         guint8 *s,
                                                         guint8 *f);

Converts LBA sector address stored in lba into MSF address, storing each field into m, s and f, respectively.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

lba :

LBA address. [in]

diff :

account for the difference. [in]

m :

location to store minutes, or NULL. [out][allow-none]

s :

location to store seconds, or NULL. [out][allow-none]

f :

location to store frames, or NULL. [out][allow-none]

mirage_helper_lba2msf_str ()

gchar *             mirage_helper_lba2msf_str           (gint lba,
                                                         gboolean diff);

Converts LBA sector address stored in lba into MSF address.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

lba :

LBA address. [in]

diff :

account for the difference. [in]

Returns :

a newly-allocated string containing MSF address; it should be freed with g_free() when no longer needed.

mirage_helper_msf2lba ()

gint                mirage_helper_msf2lba               (guint8 m,
                                                         guint8 s,
                                                         guint8 f,
                                                         gboolean diff);

Converts MSF sector address stored in m, s and f into LBA address.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

m :

minutes. [in]

s :

seconds. [in]

f :

frames. [in]

diff :

difference. [in]

Returns :

integer representing LBA address

mirage_helper_msf2lba_str ()

gint                mirage_helper_msf2lba_str           (const gchar *msf,
                                                         gboolean diff);

Converts MSF sector address stored in msf string into LBA address.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

msf :

MSF string. [in]

diff :

difference. [in]

Returns :

integer representing LBA address or -1 on failure.

mirage_helper_sector_edc_ecc_compute_ecc_block ()

void                mirage_helper_sector_edc_ecc_compute_ecc_block
                                                        (const guint8 *src,
                                                         guint32 major_count,
                                                         guint32 minor_count,
                                                         guint32 major_mult,
                                                         guint32 minor_inc,
                                                         guint8 *dest);

Calculates ECC (error correction code) for data in src and writes the result into dest. The code assumes 2352 byte sectors. It can calculate both P and Q layer of ECC data, depending on major_count, minor_count, major_mult and minor_inc.

To calculate ECC (first P, then Q layer) for different types of sectors and store it into sector data, use:

  • Mode 1 sector:
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 86, 24, 2, 86, sector_buffer+0x81C);
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 52, 43, 86, 88, sector_buffer+0x8C8);
    
  • Mode 2 Form 1 sector:
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 86, 24, 2, 86, sector_buffer+0x81C); \n
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 52, 43, 86, 88, sector_buffer+0x8C8);
    

(This is assuming all other sector data, including EDC, is already stored in sector_buffer and that sector_buffer is 2532 bytes long)

src :

data to calculate ECC data for. [in]

major_count :

major count. [in]

minor_count :

minor count. [in]

major_mult :

major multiplicator. [in]

minor_inc :

minor increment. [in]

dest :

buffer to write calculated ECC data into. [out caller-allocates]

mirage_helper_sector_edc_ecc_compute_edc_block ()

void                mirage_helper_sector_edc_ecc_compute_edc_block
                                                        (const guint8 *src,
                                                         guint16 size,
                                                         guint8 *dest);

Calculates EDC (error detection code) for data in src of length size and writes the result into dest.

To calculate EDC for different types of sectors and store it into sector data, use:

  • Mode 1 sector:
    mirage_helper_sector_edc_ecc_compute_edc_block(sector_buffer+0x00, 0x810, sector_buffer+0x810);
    
  • Mode 2 Form 1 sector:
    mirage_helper_sector_edc_ecc_compute_edc_block(sector_buffer+0x10, 0x808, sector_buffer+0x818);
    
  • Mode 2 Form 2 sector:
    mirage_helper_sector_edc_ecc_compute_edc_block(sector_buffer+0x10, 0x91C, sector_buffer+0x92C);
    

(This is assuming all other sector data is already stored in sector_buffer and that sector_buffer is 2532 bytes long)

src :

data to calculate EDC data for. [in][array length=size]

size :

size of data in src. [in]

dest :

buffer to write calculated EDC data into (4 bytes). [out caller-allocates][array fixed-size=4]

mirage_helper_strcasecmp ()

gint                mirage_helper_strcasecmp            (const gchar *str1,
                                                         const gchar *str2);

Replacement function for g_strcasecmp/strcasecmp, which can properly handle UTF-8. Glib docs state this is only an approximation, albeit it should be a fairly good one.

It compares the two strings str1 and str2, ignoring the case of the characters. It returns an integer less than, equal to, or greater than zero if str1 is found, respectively, to be less than, to match, or be greater than str2.

str1 :

first string. [in]

str2 :

second string. [in]

Returns :

an integer less than, equal to, or greater than zero if str1 is found, respectively, to be less than, to match, or be greater than str2.

mirage_helper_strncasecmp ()

gint                mirage_helper_strncasecmp           (const gchar *str1,
                                                         const gchar *str2,
                                                         gint len);

Replacement function for g_strncasecmp/strncasecmp, which can properly handle UTF-8. Glib docs state this is only an approximation, albeit it should be a fairly good one.

It compares first len characters of string str1 and str2, ignoring the case of the characters. It returns an integer less than, equal to, or greater than zero if first len characters of str1 is found, respectively, to be less than, to match, or be greater than first len characters of str2.

str1 :

first string. [in]

str2 :

second string. [in]

len :

length of string to compare. [in]

Returns :

an integer less than, equal to, or greater than zero if first len characters of str1 is found, respectively, to be less than, to match, or be greater than first len characters of str2.

mirage_helper_subchannel_deinterleave ()

void                mirage_helper_subchannel_deinterleave
                                                        (gint subchan,
                                                         const guint8 *channel96,
                                                         guint8 *channel12);

Deinterleaves subchannel data of type subchan from subchannel data stored in channel96 and writes the resulting subhcannel data into subchannel12.

subchan :

subchannel type. [in]

channel96 :

buffer containing subchannel data to deinterleave (96 bytes). [in][array fixed-size=96]

channel12 :

buffer to deinterleave subchannel data into (12 bytes). [out caller-allocates][array fixed-size=12]

mirage_helper_subchannel_interleave ()

void                mirage_helper_subchannel_interleave (gint subchan,
                                                         const guint8 *channel12,
                                                         guint8 *channel96);

Interleaves subchannel data of type subchan stored in channel12 into subchannel data stored in subchannel96.

subchan :

subchannel type. [in]

channel12 :

buffer containing subchannel data to interleave (12 bytes). [in][array fixed-size=12]

channel96 :

buffer to interleave subchannel data into (96 bytes). [out caller-allocates][array fixed-size=96]

mirage_helper_subchannel_q_calculate_crc ()

guint16             mirage_helper_subchannel_q_calculate_crc
                                                        (const guint8 *data);

Calculates the CRC-16 checksum of the Q subchannel data stored in data.

data :

buffer containing Q subchannel data (10 bytes). [in][array fixed-size=10]

Returns :

CRC-16 checksum of Q subchannel data

mirage_helper_subchannel_q_decode_isrc ()

void                mirage_helper_subchannel_q_decode_isrc
                                                        (const guint8 *buf,
                                                         gchar *isrc);

Decodes ISRC stored in buf into string isrc.

buf :

buffer containing encoded ISRC (8 bytes). [in][array fixed-size=8]

isrc :

string to decode ISRC into (12 bytes). [out caller-allocates][array fixed-size=12]

mirage_helper_subchannel_q_decode_mcn ()

void                mirage_helper_subchannel_q_decode_mcn
                                                        (const guint8 *buf,
                                                         gchar *mcn);

Decodes MCN stored in buf into string mcn.

buf :

buffer containing encoded MCN (7 bytes). [in][array fixed-size=7]

mcn :

string to decode MCN into (13 bytes). [out caller-allocates][array fixed-size=13]

mirage_helper_subchannel_q_encode_isrc ()

void                mirage_helper_subchannel_q_encode_isrc
                                                        (guint8 *buf,
                                                         const gchar *isrc);

Encodes ISRC string isrc into buffer buf.

buf :

buffer to encode ISRC into (8 bytes). [out caller-allocates][array fixed-size=8]

isrc :

ISRC string (12 bytes). [in][array fixed-size=12]

mirage_helper_subchannel_q_encode_mcn ()

void                mirage_helper_subchannel_q_encode_mcn
                                                        (guint8 *buf,
                                                         const gchar *mcn);

Encodes MCN string mcn into buffer buf.

buf :

buffer to encode MCN into (7 bytes). [out caller-allocates][array fixed-size=7]

mcn :

MCN string (13 bytes). [in][array fixed-size=13]

mirage_helper_calculate_crc16 ()

guint16             mirage_helper_calculate_crc16       (const guint8 *data,
                                                         guint length,
                                                         const guint16 *crctab,
                                                         gboolean reflected,
                                                         gboolean invert);

Calculates the CRC-16 checksum of the data stored in data.

data :

buffer containing data. [in][array length=length]

length :

length of data. [in]

crctab :

pointer to CRC polynomial table. [in][array fixed-size=256]

reflected :

whether to use the reflected algorithm. [in]

invert :

whether the result should be inverted. [in]

Returns :

CRC-16 checksum of data

mirage_helper_calculate_crc32 ()

guint32             mirage_helper_calculate_crc32       (const guint8 *data,
                                                         guint length,
                                                         const guint32 *crctab,
                                                         gboolean reflected,
                                                         gboolean invert);

Calculates the CRC-32 checksum of the data stored in data.

data :

buffer containing data. [in][array length=length]

length :

length of data. [in]

crctab :

pointer to CRC polynomial table. [in][array fixed-size=256]

reflected :

whether to use the reflected algorithm. [in]

invert :

whether the initial value and result should be inverted. [in]

Returns :

CRC-32 checksum of data